Sheetflow Construction Erosion and Sediment Control

February 11, 2020

Locating Check Dams in a Ditch Line Part 2

November 5, 2019

Inspecting Sand Bag Check Dams

How to inspect sand bag check dams.

January 25, 2017

Straw Bales Don’t Work as Check Dams

Straw bales installed in ditch lines with water flows is a mistake. Water goes under and around, causing erosion, rather than backing up behind to allow sediment to settle. Check dams need to have a center point that is 6 to 12 inches lower than the outer edges so that water flows over the top, rather than around the sides. You can’t do this with straw bales. For this reason, these are not allowed to be used as check dams in the state of Washington.

August 14, 2016

Check Dams are Great But Do Not Reduce Turbidity

Check dams are used in ditches to slow the velocity of flowing water, reducing erosive potential. An additional benefit of check dams is to allow some sedimentation in the ponded water behind the dam. Sand and some larger silt can be removed using check dams; colloidal particles cannot. These microscopic particles, with a negative electrical charge, resist sedimentation and are the chief cause of turbidity, or cloudiness of the water. This video clearly shows that the turbidity of water flowing in a ditch is the same after traveling through 8 check dams.

May 17, 2016

Inspecting-Check Dams Need Low Center Point

Check dams need to be installed so that the center point of the dam is at least 6 to 8 inches lower than the outside edge; 12 inches in areas where intense rainfall occurs. If the center point is higher than the outer edges, water will run around the dam and erode the side slopes of the ditch, causing erosion. If the ditch is shallow and you are using triangular silt dikes, you might need to add sand bags to create a center point that is low.

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